The Discovery of Rhabdopleura (Pterobranchia) in the Jurassic of Poland

A eTA PAL A EON T 0 LOG I CAP 0 LON ICA Vol. XIV 1969 No.4

CYPRIAN KULICKI

THE DISCOVERY OF RHABDOPLEURA (PTEROBRANCHIA) IN THE JURASSIC OF POLAND

Abstract. - Fragments of tubarium of Rhabdopleura kozlowskii n.sp., etched from calcareous concretions occurring in Callovian clays in Lapiguz clay pit in Luk6w are described. Comparisons with the species Rh. vistulae Kozlowski from Danian of Poland and the Recent Rh. normani Allman fmm Norway have shown that Rh. kozlowskii n. sp. more strongly resemb1es the Recent species.

INTRODUCTION

The genus Rhabdopleura Allman, 1869 is represented in Recent seas by the following three species: 1) Rh. normani Allman, 1869, occurring in the northern hemisphere from the Lofoten to the Azores and from the western coasts of Greenland to the Bay of Biscay, where it lives at a depth of 5-600 m, temperature of 5-12°C and salinity of 33-35%0 (Burdon Jones, 1954); 2) Rh. striata Schepotieff, 1909, found on coral reefs near Ceylon at a depth of 2-15 m (Schepotieff, 1909); 3) Rh. annulata Norman, 1912, living near Celebes, New Zealand, Tasmania and the coasts of South Australia, at a depth of 75-549 m (Johnston, 1937; Hyman, 1959). We cannot be sure, however, if the species Rh. annulata is not conspecific with Rh. normani. If such would be the case, the genus Rhabdopleura would be represented in the Recent fauna by two species only. In the fossil state, only two species, i.e. Rh. eocenica Thomas & Davis, 1949 from Eocene of England and Rh. vistulae Kozlowski, 1956 from Danian of Poland have been known so far. Rh. kozlowskii n.sp., described in the present paper, is the third and the oldest representative of this genus found in the fossil state. Its remains were separated by etching from a calcareous concretion, about 30 kg in general weight, found in black Callovian clays in a clay pit Lapiguz in Luk6w about 100 km south-east of Warsaw. 538 CYPRIAN KULICKI

The Callovian clays outcropped in Luk6w make up an erratic mass of northern origin 1 sq km in area, in Quaternary formation. The clays themselves are almost completely devoid of fauna, but the concretions, occurring in them, contain a rich and well-preserved fauna (ammonites, pelecypods, gastropods, belemnites) and, sometimes, even debris of wood. The concretions are also met with which apparently are unfossiliferous but, after dissolving them in hydrochloric acid, many spicules of sponges may be found in the residue. The concretions have varying diameters, on the average of 30 em. ClaJte~mineralsand bituminous substances they contain give them a black or gray colouration. Views concerning the stratigraphic position, origin of concretions and concentration of organisms they contain were presented by Makow slu--(1952). Ammonites from concretions, Kosmoceras jason (Reinecke), K. spinosum (Sowerby) and Peltoceras athleta (Philips)' determine the age of the days as the Middle and the lowermost part of the Upper Callovian. The effect of waving (Makowski, 1952, p. IX) was probably one of the conditions of forming concretions which would be an evidence of a not very great depth of the basin. Debris of wood and spores of land plants indicate a small distance from the shore. Approximate conditions of life of Rh. kozlowskii n. sp. may be reproduced on the basis of these facts. The remains of Rhabdopleura occur both in the concretions containing shells' of. molluscs and' fragments of wood and in those lacking such remains. Fragments of periderm of hydroids, scolecodonts, organic linings of tests of forminifers and abundant plant remains such as wood, macro spores, dinoflagellates, hystricospheres, cuticles and many other unident ified remains were etched together with the remains of Rhabdopleura from these some concretions. The colonies of Rh. kozlowskii n. sp. probably settled on shells of molluscs, pieces of wood and sponges which were resting on the bottom of a not very deep sea. Rh. kozlowskii n. sp. is likely to have identical ecological requirements with those of the Recent Rh. normani. The specimens of Rh. kozlowskii n. sp., described in the present paper, are housed at the Palaeozoological Institute of the Polish Academy of Sciences in Warsaw for which the abbreviation Z. Pal. is used. I would like to express my heartfelt thanks to Prof. R. Kozlowski (Palaeozoological Institute, Polish Academy of Sciences, Warsaw) and Docent A. Urbanek (Palaeozoological Laboratory of the Warsaw Univer sity) for their valuable remarks and advice which were very helpful in my work. THE DISCOVERY OF RHABDOPLEURA 539

DESCRIPTION

FamiJIy Rhabdopleuridae Harmer, 1905 Genus Rhabdopleura- Allman, 1869 Rhabdopleura kozlowskii n. sp. (Text-figs. 1-6)

Cotypi: A stolon in Fig. 4A; a zooidal tube in Fig. IE; a· stolonal tupe in Fig. 3B; cysts of sterile buds in Fig. 5J. Collection numbers: Z. Pal. Pb. 1/38, 45, ?9, 24. Locus typicus: Lapiguz clay pit, Luk6w, Poland. Stratum typicum: Callovian, Kosmoceras jason, K. spinosum and PeLioceras athLeta zones. Derivatio nominis: Named in honour of Prof..Roman Kozlowski, an investigator of fossil hemichordates.

Diagnosis. - Zooidal and stolonal tubes similar.in size to those in Rh. normani. Fuselli of stolonal tubes much more frequently arcuate than those in Rh. vistulae, Rh. eocenica and Rh. normani. In transverse section, stolons semicircular as in Rh. normani. Peduncular stolons short and provided with 1-3 diaphragms. Material. - Fragmentary zooidal tubes - 340 speGimens; cysts of ster ile buds - 180; stolonal tubes - 35; zooidal tubes with a creeping part 11; stolons - 20. Description. - Zooidal tubes (Fig. 1). Broken and rarely occurring in fragments longer than 0.5 mm, not flattened. In regard to the state of preservation, they resemble zooidal tubes of Recent specimens from which they differ, however, in a much stronger pigmentation of the walls. In more.-l;han 60 measurements, the diameter of these tubes, the width of fusellar collars not taken into account, varied within limits of 115 and 207 I-l (on the average, 155 I-l). Together with fusellar collars, these dimensions amounted to 139-241 I-l (on the average, 182 I-l). The differen ces between these vah,les give a certain notion of the width of fusellar collars. Their width varies within limits of 12 and 21 /.1, the most often met with being 15 I-l wide. There is a certain interdependence between the diameter of tubes and width of collars: tubes with a small diameter have somewhat narrower fusellar collars than those in tubes with large diameters. The width of fuselli of zooidal tubes also displays a consider able variability: between 18 and 62 I-l (averaging 37 I-l). On the other hand, no correlation is observed between the diameter of tubes and the width of fuselli. Although the largest mean width of fuselli is recorded in tubes with a large diameter, the tubes with small diameters frequently have wider fuselli than those in tubes with larger diameters (Table 1). The thickness of walls of zooidal tubes, measured in optical sections, fluctuated within limits Of 7 and 14 I-l (averaging 10 I-l). The thickness o

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Fig'. 1. - Rhabdopleura kozlowskii n.sp. A-C zooidal tubes with small diameters (Z. Pal. Pb. 1/45-47), D-K zooidal tUbes with most frequent diameters (Pb. V33, 44, 48-52, 102), E a ootype. THE DISCOVERY OF RHABDOPLEURA 541

No. of spec.

'10

diem. ~n "u. 120 140 160 180 200 220 Fig. 2. - Frequency distribution <;urve of zooidal tubes diameter, drawn on the basis 'of specimens etched from two ·concretio·ns. of a wall, measured on microtomic sections amounts to 0.5-1.00 1-1-. This difference probably results from a decrease in the volume of the substance of which tubes are formed as an effect of dehydration of specimens in alcohol and xylene. The walls of zooidal tubes in the proximal part are always thicker than in the distal part. Zooidal tubes with smallest diameters (115-122 1-1-) considerably differ in appearance from the remain ing ones, their fuselli (Fig. 1 A-C) being wide in proportion to the diameter. The observation may be also made that the curve is bimodal: one with a diameter of 118 1-1-, and the other with a diameter of 168 1-1 (Fig. 2). Stolonal tubes (Fig. 3). The basal wall of stolonal tubes, which during the animal's life time directly adheres to the substratum, is as a rule destroyed so that most specimens examined are devoid of it. Some of a few specimens with the basal wall preserved have also stolons. The wall itself is considerably thinner than the wall with a zigzag suture. One of the specimens is preserved together with a fragment~ry cyst of a sterile bud and three with septa. Almost all stolonal tubes are bordered by a narrow Ifarginal membrane. The width of these tubes measured on ten specimens, without taking into account the marginal membrane, fluctuates within limits of 126 and 163 1-1- (on the average, 145 1-1-). A still clearer idea concerning the width of stolonal tubes is imparted by the width of cysts of sterile buds which were enclosed in stolonal tubes and strongly adhered to their walls. These measurements, o i:, 3 3

Fig. 3 THE DISCOVERY OF RHABDOPLEURA 543 taken on a considerable number of specimens, display a fluctuation within limits of 97 and 255 J..L (averaging 162 J..L). The width of fuselli of stolonal tubes also displays a considerable variability (22-58 J..L, averaging 42 J..L). No smaller variability is recorded in the tubes which belong to one and the same colony (bifurcated tubes) and in which fuselli 49, 51, 51J..L wide occur succeeding each other. In the lateral branch there are fuselli 33, 35, 32 J..L wide. Fuselli occurring on both sides of a stolonal tube join each other at a certain angle. The apex of this angle points usually to the proximal en~ of tube, but in some cases of Rh. normani Allman, illustrated bySchepotieff (1907), PI. 17, Figs. 2, 4) an opposite orientation was observed. In Rh. striata Schepotieff, 1909, apexes of angles formed by fuselli are directed distally (Schepotieff, 1909, PI. 7, Fig. 7). In the specimens of Rh. kozlowskii n. sp. examined, in the points in which the bifurcation of the tube or stolon or the position of the zooidal tube unequivocally determine the proximal and the distal part of a specimen, fuselli form an obtuse angle whose apex in all cases points proximally. In Rh. kozlowskii n. sp. these fuselli are, as a rule, arcuate and only infrequently straight. Stolons (Fig. 4). In transverse section, stolons are semicircular, with a flat lower and convex-semicircular upper wall. The flat wall is very rarely preserved. In specimens in which this wall is preserved fragment ary, one can ascertain that it is many times thinner than the convex wall. The width of stolons fluctuates within limits of 17 and 53 J..L (averaging 31 J..L) and the width also considerably varies within one and the same stolon (28-53 J..L). The largest width is reached by stolons before bifur cations or before the points in which peduncular stolons detach them selves. Peduncular stolons, which are attachment places of a contractile peduncle of zooid or which are connected with the lumen of cysts of sterile buds, are situated alternately on the left and on the right side of the main stolon at intervals of, on the average, about 480 J..L. The smallest distance observed amounted to 271 J..L, the largest 989 ~L. Pedun cular stolons are vesicular and mostly have two diaphragms, a basal and a distal one, with pores 3-12 J..L in diameter (averaging 6 J..L). Pores in both diaphragms may be equal or varying in diameter. The walls of diaphragm may be distally bent around a pore. In the case when a stolon bifurcates in the place in which a lateral stolon is formed, it usually starts with a vesicle having two diaphragms.and resembling a peduncular

Fig. 3. - Rhabdopleura kozlowskii n.sp. A,C,F stolonal tubes (Z. Pal. Pb. 1/34-36); B a bifurcated stolonal tube with a bifurcated stolon and with a transverse septum (Pb. 1/29), a cotype; D a stolonal tube with stolon (Pb. 1/31); E a stolonal tube with stolon and septum (Pb. 1/30); G-I zooidal tubes with a creeping part (Pb. 1/28, 32, 37). 544 CYPRIAN KULICKI

O.2mm !

Fig. 4. - Rhabdopleura kozlowskii n.sp. A,B,D,F bifurcated stolons with peduncular stolons (Z. Pal. Pb. I/38, 40,41,43); A a cotype; C,E fragmentary stolons (Pb. 1/42,43); G,H stolons with cysts of sterile buds (Pb. 125, 26). stolon. In one case, two successive vesicles were observed with three diaphragms (Fig. 4A) behind which a lateral stolon runs. On one of the specimens, having a stolonal vesicle, a subsequent bifurcation was visible 0.5 mm I

Fig. 5. - RhabdopLeura kozLowskii n.sp. A-J cysts of sterile buds (Z. PaL Pb. 111-10, J a cotype.

4 Acta Palaeontologica nr 4/69. 546 CYPRIAN KULICKI in which vesicles were not formed, but two successive diaphragms (Fig. 4F) were situated in the lateral stolon at some distance behind the place of bifurcation. The size of pores in these diaphragms is variable but equalling that in diaphragms of peduncular stolons. Bifurcated stolons, in which a peduncular stolon detaches itself from the lateral stolon just behind the point of bifurcation, are frequently observed. Cysts of sterile buds (Fig. 5). The cysts are found either as isolated elements, or together with stolons. Short peduncular stolons which con nect the main stolon with the proximal part of cysts are very often devoid of the basal diaphragm (Fig. 4 G-H), so that in most cases, the inside of a cyst is separated from the inside of a stolon by only one diaphragm having a small pore. The cysts of sterile buds adhered closely to the walls of stolonal tubes. The following facts make up the evidence for this statement: 1) in most of the cysts, impressions of fuselli are preserved on the outer surface of the wall; 2) in specimens with the lower wall preserved, stolon is always embedded in and fused with it; 3) a very close adherence of both elements is observed in a specimen of stolonal tube with a fragmentary cyst of sterile bud. Upper walls of cysts are convex, semicircular or slightly flattened and considerably thicker than the lower ones. The width of cysts varies from 97 to 255 f.1 (averaging 162 f.1) and the length from 300 to 681 f.1. An average length of a cyst is more than twice as large as width, although wide and short, or narrow and long or even irregularly shaped cysts are also found (Fig. 6). The frequent occurrence of cysts of sterile buds is most likely the result of a considerable degree of their resistance. In some samples,

Fig. 6. - Rhabdopleura kozlowskii n.sp. Diagrams of the different stolons and diaphragms observed. THE DISCOVERY OF RHABDOPLEURA 547 no other remains of Rh. kozlowskii n. sp. were found, but the cysts of sterile buds only. Comparisons. - Rhabdopleura kozlowskii n. sp. may be fully compared with Rho vistulae Kozlowski and Rho normani Allman. The comparison with Rho eocenica Thomas & Davis is impossible because of a dif ferent degree of preservation of specimens of this species (pyritization) and the lack of some anatomical elements. In regard to their dimensions, the zooidal tubes of Rho vistulae, Rh. eocenica and Rh. kozlowskii n. sp. do not differ from each other to any significant extent. The range of variability of the diameter of tubes and width of fuselli is given in Table 20 The number of these same elements, known in Rh. eocenica and Rh. vistulae was more limited and, besides, they were not so well preserved. This might be the reason why the greatest variability of these elements was observed in Rho kozlowskii n. sp. The tubes with smaller and larger diameters which occurred toge ther in Rh. kozlowskii n. sp. might be also a manifestation of sexual dimorphism. Stolonal tubes of the species compared also do not differ in size from each other to a significant extent. All other species compared may be also placed within this range of variability. The width of fuselli of stolonal tubes in Rh. kozlowskii n. spo is, on the average, smaller than that in Rh. normani and both fossil species and the fuselli of Rho kozlo wskii n. sp. are more strongly arcuate than those of Rh. normani, Rh. vistulae and Rh. eocenica. The width of stolons in Rh. kozlowskii n. spo is, on the average, slightly larger than that in the remaining species. The transverse section through a stolon of the new species is, in all cases, semicircular, with characteristic triangular margins and a very thin lower wall, i.e. identical as that in Rh. normani (Schepotieff, 1906; PI. 33, Figs. 5, 9) and different than that in Rh. vistulae, in which it is rounded (Kozlowski, 1956. Fig. 1). On the other hand, peduncular stolons of Rh. kozlowskii n. sp. are similar in structure to these elements in Rh. vistulae. They are short, vesicular and provided with 1-3 diaphragms having pores. Peduncular stolons, adhering to cysts of sterile buds, frequently have only one distal dia phragm. Such a structure of peduncular stolons clearly differs Rh. kozlowskii n. sp. from Rh. normani. In Rh. kozlowskii n. sp. branching lateral stolons are most frequently separated from the main stolon by a short, vesicular stolon having two diaphragms. This vesicular stolon strongly resembles peduncular stolons. Such a structure is never met with in Rh. vistulae. In Rh. normani, only diaphragms situated in lateral stolon occur instead of short, vesicular stolons. Such diaphragms may be also met with in Rho kozlowskii n. spo behind or before the place in which stolons bifurcates (Fig. 5). In a general outline, Rho kozlowskii

4" Table 1 Comparative table of measurements of some elements of tubarium (in ~l)

Rhacdopleura kozlowskii n. sp. Rh. vistulae'* Rh. normani '* -- No. of specimens diameter width of width of z. Pal. Pb. without with width of fuselli average diameter I fuselli diameter fuselli collars I collars --- I/105 207 241 48 62 46 58 54 160 39 172 34 1/104 183 215 44 46 53 44 46 37 45 172 39 180 24 I/103 170 200 35 44 39 39 39 37 40 38 38 37 37 38 176 46 184 37 Ul ClJ .0 I/48 164 190 35 32 35 24 35 30 28 28 30 25 30 28 18 29 186 40 205 25 E I/44 162 187 26 35 29 32 29 36 32 36 36 30 32 195 39 206 30 C;; '0 lI107 155 175 22 25 28 28 30 32 30 32 39 30 ·0 0 I/1C6 148 175 28 35 37 32 30 39 35 30 33 N I/47 122 152 35 35 55 36 36 31 31 32 32 34 I/46 122 148 43 39 40 41 35 43 39 40 1/45 115 12,9 33 38 36 38 36 40 41 36 28 36 i ----

width width width

I/34 163 44 41 38 41 51 43 37 41 46 42 148 49 168 52 I/36 162 41 45 33 36 48 47 41 207 72 172 57

Ul 11108 156 54 53 40 41 43 49 38 39 46 45 216 62 I 176 53 ClJ .0 E I/109 147 36 38 40 43 39 252 57 182 52 ..... I/35 143 23 22 30 31 33 35 30 35 29 30 I ellc 0 I/3t 154 53 55 54 0 U5 I/37 129 30 31 35 35 33 25 24 25 41 31 1/29 127 33 35 32 32 37 33 35 34 lateral branch 49 48 46 49 51 51 49 1/30 126 48 49 47 32 38 27 58 51 44 I THE DISCOVERY OF RHABDOPLEURA 549

Table 2

Comparative table of measurements of tubarium (in J.l)

: Rh. eocenica Rh. Rh.normani Rh. vistutae Elements mEasured Thomas & koztowskii Allman Davis Kozlowski n. sp.

I Diameter of zooidal tube with collars 152-184 174-~28* 13<:-200* I 139-241 Diameter of zooidal tube without collars - - - 115-207 Width of fusellus in zooidal tube 17-40 40-45 34-50 18-62 Width of stolonal tube 168-182 150-195 148-252 126-163 Width of fusellus in stolonal tube 17-62 60-72 39-105 22-58 Width of stolon Hj-42 22 14-35 17-53 Width of cysts of sterile buds I 147-156 - - 97-255 Width of zooidal tubes wall 4-14 - -- 7-14 Distance between peduncular stolons - 220-640** 300-900 271-989

* Zooidal tubes more or less flattened. ** Distance between woidal tubes corresponding approximately to the distance between peduncular stolons. n. sp. is more similar in the structure of stolons as in the structure of cysts of sterile buds - to Rh. normani than to Rh. vistulae. A peduncular stolon is always connected with the cyst in the latter's proximal part as is the case in Rh. normani, whereas in Rh. vistulae Kozlowski the attachment place is always slightly shifted distally (Kozlowski, 1956). In Rh. kozlowskii n.sp. main stolon is depressed and fused with the lower wall of cyst as is the case in Rh. normani Allman and in contrast to that Rh. vistulae Kozlowski (Kozlowski, 1956). It is clear from this comparison that the elements of tubarium in Rhabdopleura are only slightly variable evolutionally and the largest differences are obser ved in the structure of stolons. Rh. kozlowskii n. sp. in many respects resembles the Recent Rh. normani rather than the Danian Rh. vistulae and the Recent species may be more easily derived from the new Jurassic species here described than from the Danian one.

PaLaeozooLogicaL Institute of the Polish Academy of Sciences Warszawa, 2wirki i Wigury 93 June, 1969 550 CYPRIAN KULICKI

REFERENCES

BURDON-JONES, C. 1954. The habitat and distribution of Rhabdopleura normani Allman.-Naturvitensk. rekke, 11, 3-17, Bergen. HYMAN, H. 1959. The Invertebrates. 5, 179-191, New York. JOHNSTON, T. H ..1937. Australian Antarctic Expedition 1911-1914. - Sci. Reports, Ser. C, Zoot Botany, 3, 4, 2-8, Sydney. KOZLOWSKI, R. 1956. Sur Rhabdopleura du Danien de Pologne (Rhabdopleura z danu Polski). - Acta Palaeont. Pol., 1, 1, 2-21, Warszawa. MAKOWSKI, H. 1952. La faune callovienne de Luk6w en Pologne (Fauna kelowejska z Lukowa). - Palaeont. Pol., 4, I---'X+ 1-64, Warszawa. SCHEPOTIEFF, A. 1906-1908. Die Fterobranchier. - Zoot Jb. Anat. etc. (2), 23/24, 463-534, 193-238, Jena. - 1909. Die Pterobra:nchier des Indischen Ozeans. - Zool. Jb. Syst. etc. (1), 28, 429-448, Jena. THOMAS H. D. & DAVIS, A. G. 1949. A fossil 1species of the pterobranch Rhab dopleura. - Abstr. Proe. Geol. Soc. London, 1450, p. 79, London. -&- 1949. The Fterobranch Rhabdopleura in English Eocene. - Bull. Brit. Mus. (Nat. Rist.), Geol., 1, 1, 1-19, London.

CYPRIAN KULICKI

ODKRYCIE RRABDOPLEURA (PTEROBRANCHIA) W JURZE POLSKI

Streszezenie

W pracy tej podany jest opis cZllsci szkieletowych kolonii Rhabdopleura All man, 1869 (Fterobranchia), odkrytych przez autora w konkrecjach z How kelowej skich w gliniance Lapig'Uz w Lukowie i zalic2Jonych do nowego gatunku - Rhabdo pleura kozlowskii n.sp. Zbadane zostaly rurki zoidalne, rurki stolonalne, stolony oraz cysty pqczk6w sterylnych. Dane liczbowe odnosnie wymiar6w tych element6w podane Sq w tabelach tekstu angielskiego, w zestawieniu z danymi dotyczqcymi gatunku kopalnego z danu Polski Rh. vistulae Kozl. i gatunku wsp6lczesnego Rh. normani Allman. Por6wnanie nowego gatunku z Rh. vistulae doprowadza autora do wniosku, ie gatunek kelowejski jest morfologicznie bardziej podobny do wsp6l czesnego Rh. normani, nii do Rh. vistulae. Swiadczy to 0 bardzo malych zmianach ewolucyjnych rodzaju Rhabdopleura Allman od jury do dzis. Dokladne por6wna nie Rh. kozlowskii n.sp. z gatunkiem Rh. eoeeniea Thomas & Davis, opisanym z eocenu Anglii, nie jest moiliwe, gdyi material angielski byl kompletnie spiryty zowany, co zatado drobne szczeg6ly jego budowy. THE DISCOVERY OF RHABDOPLEURA 551

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